This tamron 28 75mm f28 xr di lens incorporates a motor built into the lens itself which gives it the capability to autofocus with all nikon dslr cameras including the d40 and d40x in addition with the motor built into the lens focusing will be quieter and more responsive the 28 75mm f28 xr di lens is an ultra compact lens its compactness makes it look and feel like an ordinary standard zoom lens yet provides the versatility that a fast constant maximum aperture offers and will defi